Transcript Unit 4: Cells

Unit 4: Cells
Learning Goal 3: Identify the
function and properties of the four
major biological molecules and
water.
Water



The single most abundant compound
found in living things.
One of the few compounds that are liquid
at the temperature found over much of the
Earth’s surface.
Expands as it freezes. Ice is less dense
than water.
pH Scale
Section 2-2
Increasingly Basic
Oven cleaner
Neutral
Increasingly Acidic
•Water has a
pH of 7.
• This means
it is neutral.
Bleach
Ammonia solution
Soap
Sea water
Human blood
Pure water
Milk
Normal
rainfall
Acid rain
Tomato
juice
Lemon juice
Stomach acid
Figure 2-9 NaCI Solution
Section 2-2
ClWater
Water is a
universal solvent.
Cl+Na
Water
Na+
Water
 H2O


It is a neutral molecule (10 protons and 10
electrons).
A water molecule is polar because there is an
uneven distribution of electrons between the
oxygen and the hydrogen atoms.
• Because of it is a polar molecule the water molecules
can be attracted to one another forming hydrogen
bonds.

These bonds are not as strong as covalent or ionic bonds.

Water is cohesive.
• Cohesion is an attraction
between molecules of the
same substance.

This causes water to form
drops on a smooth surface, or allows paperclips to
float.
• Adhesion is an attraction between molecules of
different substances.

This allows water to creep up from the roots of plant
to the very top of the plant (capillary action).
Organic Macromolecules

http://teachertube.com/viewVideo.php?video_id=43698
 Formed
by a process known as
polymerization.

Large compounds are built by joining
smaller ones together.
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Monomers = smaller units
Polymers = joined together
monomers.
Carbohydrates
http://streaming.teachertube.com/viewVideo.php?title=Carbohydrates&video_id=43700

Made of carbon, hydrogen, and oxygen
usually in a 1:2:1 ratio.
 Living things use carbohydrates as their
main source of energy.

Monosaccharide
• A single sugar molecule.


Glucose, galactose, and fructose.
Polysaccharides
• Large macromolecules formed from monosaccharides.

Many animals store glycogen.
• Plant use plant starch and cellulose.
Figure 2-13 A Starch
Section 2-3
Starch
Glucose
Lipids
http://www.teachertube.com/viewVideo.php?video_id=43703

Generally not soluble in
water.
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Made mostly from carbon
and hydrogen.
Common categories are
fats, oils, and waxes.
Lipids can be used to
store energy. Some are
an important part of
membranes and
waterproof coverings.
Lipids

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Saturated – the fatty
acids contain the
maximum possible
number of hydrogen
atoms.
Unsaturated – The fatty
acid contains at least
one carbon to carbon
double bond.
Polyunsaturated means
that it contains more
than one double bond.
Nucleic Acids
http://www.teachertube.com/viewVideo.php?video_id=43705&title=Nucliec_Acids


Contain hydrogen,
oxygen, nitrogen,
carbon, and
phosphorus.
Polymers assembled
from nucleotides.

Nucleotides consist of
three parts: a 5-carbon
sugar, a phosphate
group, and a nitrogenous
base.

There are two types
of nucleic acids.
• Ribonucleic Acid
(RNA)
• Deoxyribonucleic
Acid (DNA)

Nucleic acids store
and transmit
heredity, or genetic,
information.
Proteins
http://www.teachertube.com/viewVideo.php?video_id=43704

Contain nitrogen, carbon,
hydrogen, and oxygen.
 Polymers of amino acids.
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Some proteins control the rate of reactions and
regulate cell processes.
Some proteins are used to form bones and
muscles.
Some proteins are used to transport substances
into or out of the cell.
Some proteins are use to fight disease.
Figure 2-16 Amino Acids
Section 2-3
Amino
group
Carboxyl
group
General structure
Alanine
Serine
Figure 2-17 A Protein
Section 2-3
Amino
acids
 Proteins
have 4 levels of
organization
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1st level is the sequence of amino acids in the
protein chain,
2nd level is the amino acids can be twisted within
the chain.
3rd level is the chain
itself may be folded.
4th level is if a protein has
more than one chain, each
chain has a specific
arrangement.